Stream Control Transmission Protocol (SCTP) is a transport layer protocol used for the transport of data in a network. SCTP can transport multiple data streams by aggregating multiple data streams into a single managed bundle. This single managed bundle shares common characteristics, such as same communication path and start and end points. As a result, connection information that would have been transmitted over multiple data streams can be handled and managed as connection information of a single bundle.
The properties of SCTP make it ideal for use as a transport protocol for wide area network (WAN) optimization. It should be appreciated that WAN optimization devices can create an SCTP tunnel between them that carries compressed and optimized traffic that has been proxied at the edges. For example, an SCTP tunnel can be created between network devices to provide a proxy tunnel for a multitude of Transmission Control Protocol (TCP) sessions. This proxy with the SCTP tunnel is implemented such that multiple TCP sessions can be multiplexed or aggregated into a single (or multiple) managed SCTP association(s).
Another area of WAN optimization is the matching of available communication paths to specific user applications based on transmission and/or path characteristics. For example, voice traffic is best transmitted over a communication path with low latency. Accordingly, a communication path with low latency can be selected for transmission of voice traffic. On the other hand, a File Transfer Protocol (FTP) session is best transmitted over a communication path with large bandwidth. Accordingly, a communication path with large bandwidth can be selected for use with an FTP session. However, with the advent of multiplexing multiple TCP sessions into an SCTP tunnel, the traffic characteristics are hidden or not visible because the TCP sessions are encapsulated in SCTP. Without the visibility into the traffic characteristics, communication paths cannot be matched with specific user applications.